Crank-case ventilation



June 3, 1930. c. l.. MccUEN CRANK CASE VENTILATIONy Filed May 2, 1928UNITED STATT-:s PATENTol-FICE CHARLES L. MCCU'EN, 0F LANSING, MICHIGAN,ASSIGNOR TO GENERAL MOTORS COB- PORATION, F DETROI'L'MICHIGAN, ACORPORATION OF DELAWARE CRANE-OASE VENTILATION -Y Application led May 2X1928'. Serial No. 274,521.

This invention has to do with an arrangement for Ventilating thecrankcase of an internal combustion engine to in sure evaporation ofdiluents from the lubrlcating oil. It is characterized by the employmentof a fan to produce a circulation of air through the crankcase. Forsimplicity the fan is preferably incorporated in the iy-wheel. If theintake of the fan were directly connected to the crankcase quantities ofoil would be drawn out along with the air. To avoid this waste of oil Ihave rovided a tortuous passage between the an and the crankcase, thispassage' preferably including the usual valve chamber, and being in partformed by a baiiie directing the air stream toward the low pressure areaexisting adjacent the center of the fan. The fly-wheel is provided withthe usual housing and at the bottom of the housing I have provided aperipheral opening for the discharge of the crank-casel vapors. Thisopening preferably faces the rear of the car so that the passing aircurrents exert an aspirating vaction increasing the iow.

Figure 1 is a side elevation of an engine with parts in section showingmy improved Ventilating arrangement. l

Figure 2 is a section on line 2-2 of Figure 1.

Figure 3 is a section on line 3-3 of Figure 1.

10 indicates an internal combustion engine of the conventional L-headtype provided with valve compartments 12 at the side of the cylinders,and with the usual crankcase 14 serving as a lubricant reservoir.projects through the endv of the crankcase and carries the ily-wheel 18.The fly wheel is enclosed in the usual bell-housing 20. Air is admittedto the crankcase through the breather 22 which may be provided with acover 24 as shown, or if preferred with an air cleaner to prevententrance of grit. Upon the forward face of the flywheel 18 I havemounted blades 26 which are of the simple radial t pe shown and throwthe air outwardly. t 28 I have in- 16 indicates the crankshaft whichldicated a passage leading from the valve compartment 12. This passagecommunicates with the passage 30 form'ed by the disk 32 clamped betweenthe upper portion of the bell housing 2O andthe crankcase. This disk isof semi-circular shape as shown in Figure 3 and is cut away at thecenter to provide a center intake 33 for the fly-wheel fan. Thebell-housing 20 is provided at its lower portion with a port 34: whichmay be formed by pressing a portion of the metall of the housinginwardly as shown. The port faces rearwardly and is exposed' to theaspirating action of the passing air currents.

The operation of the device is as follows: Air entering the crankcasethrou h the breather 22 under the action of t e fan passes upwardly intothe valve chambers through the apertures 36 customarily provided aroundthe tappet guides 38 and thence passes along the valve chambers andoutwardly through passages 28 and 30 to the center of the {1y-wheel fan.Here the vapors are thrown outwardly by the action of the blades 26 andare eventually discharged through the' port 34. This discharge isfacilitated by the suction produced on the port by the air currentssweeping past it as a result of the forward motion of the car.

My system has the advantage that it is simple and that the circulationis positive and is dependent only on engine operation. The path followedby crankcase vapors in their travel toward the fan consists of the valvechambers and the 'passages 28 and 30 and is of suiiciently tortuouscharacter that oil particles are not carried along but are deposited onthe walls of the chamber and returned to the. crankcase. By locating thedischarge port 34: beneath the vehicle and at the rear I assure that thevapors do not find access to the interior of the car body and Vcausediscomfort to the passengers.

I claim:

1. In an automobile, the combination of an engine having a crankshaftand a crankcase serving as a lubricant reservoir, a centrifugal fan onthe crankshaft, a casing for t e fan. communicating with the crankcasethrough a passage extending to a point adjacent the axis of the shaft,said fan casing being provided with a peripheral discharge port, saiddischarge port facing rearwardly so as to be subject tothe aspiratingaction of passing air currents.

2. The combination of an `engine including a crankcase provided with anair inlet, a plurality of Ycylinders communicating with the crankcase, avalve compartment extending along one side of the c linders andcommunicating with the cra case, a Hywheel and a flywheel housinglocated at one end of the crankcase, said flywheel being rovided with aplurality of fan blades or the centrifugal movement of air, said enginebeing provided with a passage leading from the adjacent end of the valvecompartment to a point near the axis of the iywheel, said fiywheelhousing being provided with a peripheral port for the discharge of gasesdrawn through the crankcase.

3. In an automobile, the combination of an engine having a crankshaftand a crankcase serving as a lubricant reservoir, a centrifugal fan onthe crankshaft, a casing for the fan communicating with the crankcasethrough a passage extending to a point adjacent the axis of the shaft,said flywheel housing-being provided with a, rearwardly opening louverin its underside and adjacent its periphery, subject to the aspiratingaction of passing air currents to assist in -effecting the discharge ofvapors from the crankcase.

In testimony whereof I aiiix my signature.

CHARLES L. MCCUEN.

